/**
 * Copyright 2009 Emory University
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated  * documentation files (the 
 * "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions: The above copyright notice and this permission
 * notice shall be included in all copies or substantial portions of the
 * Software. 
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO
 * EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */
package com.markgrand.structuredSql;

/**
 * Decorator class to apply an alias to another {@link ColumnIdentifier} object.
 * 
 * @author Mark Grand
 */
class AliasedColumnIdentifier protected (val underlyingColumnIdentifier : ColumnIdentifier, 
                                         val alias : Option[String]) extends ColumnIdentifier {
  /**
   * The unqualified name of the column identified by this object. 
   */
  val columnName = underlyingColumnIdentifier.columnName

  /**
   * Return a string that uniquely qualifies that name that is the value of
   * columnName within the enclosing SQL statement. This should be an alias
   * defined within the SQL statement.
   */
  val nameQualifier=alias
}

object AliasedColumnIdentifier {
  def apply(underlyingColumnIdentifier : ColumnIdentifier) = {
    new AliasedColumnIdentifier(underlyingColumnIdentifier, None)
  }

  def apply(underlyingColumnIdentifier : ColumnIdentifier, alias : String) = {
    new AliasedColumnIdentifier(underlyingColumnIdentifier, Some(alias))
  }
}